The correct options are
B Salmonella typhimurium and Agrobacterium tumefaciens
C Bacillus thuringiensis and Pseudomonas fluorescens
The Ti plasmid of Agrobacterium tumefaciens is used as a vector to transfer the desired genes into plants while Bacillus thuringiensis produce compounds which can offer disease resistance to plants. Genes of these compounds are isolated and transferred to plants.